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How Hard is it to Integrate Renewable Energy into the Electric Grid?

Not all megawatt-hours (MWh) are created equal. The value of a MWh depends on location, dispatchability, and generator technology.

While not all MWhs are equal, we typically reward renewable and distributed generators based solely on $/MWh payments that ignore the differences of location, dispatchability, and technology.

It’s time to change the structure by which non-utility generators are paid to properly value the attributes of different MWhs.

Getting the incentives right will make integrating large amounts of intermittent wind and solar into the grid much easier.

In January, EEI said [PDF] that the incentives paid to renewable energy are going to jeopardize grid reliability and electricity costs. Many enviros have responded that this represents nothing more than the utility industry’s naked self interest. Who’s right?

I’d suggest neither. The true problem with the EEI report, as I pointed out here, is that they are confusing (perhaps intentionally) a pricing structure problem with a technology problem. There are technical issues, but they result from the structure of clean-energy incentives, not the technologies or the total volume of the incentive.

So there’s an easy solution: change the structure by which non-utility generators are paid. This is as logical as it is politically impossible. Utilities (like all businesses) are loath to set prices for the benefit of their competitors, and enviros are loath to concede that tax credits and renewable portfolio standards, won after hard-fought battles, might have structural flaws.

But it’s gotta happen. We have to decarbonize the grid as fast as possible without compromising cost or reliability — and the current status quo won’t get us there.

Here, then, is my effort to outline the key technical issues and how better economic signals might work. First, a few electricity basics you may remember from high-school physics:

Power = energy divided by time. A watt-hour is a unit of energy. A watt-hour per hour is a watt, which is a unit of power.

Electric devices need power and energy in precise volumes. Lighting a 60 watt bulb for 8 hours requires 60 x 8 = 480 watt hours — but if you try to zap the bulb with 480 watts for one hour, or dribble in one watt for 480 hours, it’s going to be dark.

Power (watts) = voltage x current.

Electric devices also need voltage and current at precise levels.

Voltage = current x resistance.

Electric power systems can be designed with “direct” or “alternating” current (this refers to whether current moves in one direction or oscillates). The modern electric grid uses alternating current (“AC”).

Now, let’s look at what follows from these six points.

First, energy storage and generation are complementary, not competitive, technologies. They can work well together, but neither is particularly good at doing the other’s job.

As a general rule, energy storage is a cheap source of power and an expensive source of energy, while energy generation is a cheap source of energy and an expensive source of power. This makes storage very good at providing short bursts and generation good at keeping the lights on. That’s why you use a battery to start your car but a gas engine to keep it going.

The time-dependent nature of energy and power makes this true even for technologies that haven’t been invented yet. The physical size of an energy storage technology is a function of how much energy it stores while the physical size of a generator is a function of its peak power output. Increasing physical size = investing more capital which is always expensive in time and dollars. By contrast, incremental decisions to open up a throttle a little wider are cheap, operating-level decisions. For energy storage, opening the throttle increases the energy extracted per unit time = power. For energy generation, opening the throttle brings in a little more fuel and generates more energy.

As a result, the lowest cost way to run a power grid will always be to maximally use energy storage technologies to meet peak power needs and maximally use generation technologies to meet energy needs. Energy storage can play a bigger role on the grid, but it won’t eliminate the need for a “just in time” linkage between generation and load.

This leads to a second issue: the grid must maintain and control generation that can instantaneously ramp up and down in response to changes in load. This informs generator technology selection and contract structure, in the sense that both are necessary, but independently insufficient.

Historically, this led grid managers to monitor load and direct generators to ramp up or down in response to load variation. As wind and solar penetration has risen, grid managers now also need to take into account sudden increases or decreases in power output from these weather-dependent generators. The result is to add complexity to grid operation in excess of that contemplated by current control/contracting schemes. With its high penetration of wind and hydro, the Pacific Northwest is at the cutting edge of these challenges. So far, they’ve developed lots of workarounds, from dumping “excess” power into resistor banks to filing lawsuits that challenge existing contracts, but they’ve not yet found a long-term, viable solution.

Third, maintaining grid reliability requires precise synchronization of voltage and current. Since power = volts x amps and since current (amps) oscillates in an AC system, voltage has to oscillate in precisely the same way. To see this visually, first consider a 60 amp, 120 volt circuit operating in perfect synchrony.

Now look at the same circuit, but with the current slightly out of phase with the voltage:

The “real” power that comes out of this circuit is still the product of volts and amps, but since the volts and amps now peak at different times, we’re getting less power than we were before (6.7 kW in this example). The ratio of actual power to theoretical power is the “power factor,” and typically runs between 85-95%. As power factor falls, generators still make the same amount of power and burn the same amount of fuel, but less gets to the load, so the effect is to lower system-wide fuel efficiency.

Motors, capacitors, and other electrical devices cause current to shift out of phase with voltage, so power factor degradation is unavoidable and grid managers must take actions to correct. The most effective way to correct is with power plants that are sited near the load and use spinning generators that can maintain constant frequency but independently shift current and voltage to offset grid degradation. This is pretty easy with any power plant that naturally spins at 2000–7000 rpm. As it turns out, this is exactly the speed that steam turbines, reciprocating engines, and gas turbines normally operate.

Unfortunately, lots of emerging generation technologies would prefer to run at lower speeds (windmills), higher speeds (microturbines), or don’t spin at all (solar panels, fuel cells). That’s not a particularly big deal, except that as these new technologies serve an ever greater portion of the load, it gets relatively harder to maintain high system power factors.

Finally, location matters. The resistance of a wire is a direct function of the length of the wire. Since voltage is the product of current and resistance, the more wires that separate a generator and the load, the greater the current (and therefore, energy) loss through that wire for any given voltage. These line losses typically run 3-5% on average, but increase dramatically during peak periods when wires are congested, often exceeding 20%. This means not only that we have to burn more fuel to generate the same amount of useful energy, but also that we must over-invest in the power generation capacity of any system with a preponderance of remote generators.

Implications

The bottom line is that not all MWh are equal:

It takes fewer MWh of generation to serve a MWh of load if that MWh is generated near the load.

The ability to produce (or curtail) peak power output at a moment’s notice is valuable regardless of actual MWh generated.

1 MWh from a generator that can boost system power factor is worth more than 1 MWh to the system. The reverse is also true.

A key point is that none of these values depend on MWh output, nor do they depend on the fuel used or power plant ownership. They depend solely on location, dispatchability, and generator technology. And yet most of the ways the rules reward generators are with $/MWh payments (PTCs, RECs, etc.) that are a function of fuel use and whether or not your ownership structure allows you to monetize tax attributes.

Which means that EEI is right when they say that current incentives for renewable energy are leading to sub-optimal capital allocation. But that’s not because renewable energy is a dangerous thing — it’s because it’s compensated in the wrong way.

In the course of putting a premium on clean energy to try and monetize externalities, we’ve created a set of economic incentives that don’t map very well against the economics of grid operation. That’s a fixable problem — but only if we first admit that there are legitimate technical issues that can be addressed with better economic signals.

Price it right, and they will come.

This would be an ideal first initiative for new Federal Energy Regulatory Commission Chairman Binz…

Thank Sean for the Post!

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Or molten fuels nuclear. After doing the math, I realize that this meltdown proof reactor should be fast tracked and distributed throught the world, otherwise the biosphere just really might fry.

So, research about grid integration is good but will the renewables exponentiate fast enough? I believe not, as there is NO way to continue subsidies for something that becomes the MAIN source of power. Instead, the ONLY way RE will power the world is when self replicating machinery makes it and its storage.

Thus, there is no argument that in the meantime, we need to switch to a nuclear (preferably a molten fuels) economy for baseload 24/7 uninteruptable power needed to replicate and power the machinery needed to suck the EXCESS co2 from the air (and to power civilization itself).

Wind and PV require a national grid far more than coal or CCGTs. In fact they require large regional grids which is why Europe is trying to connect up member countries grids.

CCGTs can be as low as 200MWe a figure small enough to power a local grid for ‘just’ a city of 100,000 people. that CCGT is all they need for the town.

Regarding nuclear build rate. France was able to build one reactor per million people over two decades . If the worlds 3 billion richest people did the same today it would mean 3000 reactors over 20 years. 3000 EPRs would generate over 41, 000TWH which is more than total worldwide demand. So build rate is not a deal breaker.

3000 reactors would actually be too much. 1500 would be enough so all the 3 billion richest people nees to do is build half as many nukes as france was able to do a generation ago.l

I really want solar and wind but believe those would take a lot more fossil fueled activity than the nuclear approach. They would also take a lot more money, since their capacity factors are are a lot less (requireing even more fossil fuels and money to build storage.

I believe we should go “all out” for the molten salt (or similar) type reactors that can’t melt down, deal with the wastes problem. and then use the nuclear to build solar, wind and storage once the tech is available to do so at a much reduced price. LFTR’s waste decays back to a normal background level in 300 years, not tens of thousands (like the unspent fuels from the light water reactor which only use about 1% of the fuel due to “fission products stressing” within the solid fuel rods), but since it decays so “fast”, it is much more hazardous in the mean time.

However, since the molten fuels reactors are so much more efficient, there would be far less wastes which can be embedded in something that only has to last 300 years.

So, if solar had to “build itself” it would take about 3 years worth of the electricity it produces (under normal conditions). If wind, only like 6 to 9 months. Fossil fuels, however, satisfies humanity’s great impatence, it can be “turned around” in much less time. Nuclear is a million times more dense than that, so there should be no problem with the electrical parts of “producing itself, solar and wind. However, the molten fuels reactor has a high enough temp to efficiently turn water into hydrogen – something that the light water reactor can only do during meltdown!

20 years is all that is required to build 500 nuclear power stations housing 2000 reactors producing 27,800TWh (EPRs) a year vs the 2035 projection of 36,600TWh demand.

That means NEW nuclear can meet 76 percent of the worlds 2035 electricity demand with most the remaining 24% provided by hydro and the better existing nukes (you can close most the 30-40 year old nukes down as the new ones will be a safer still)

2000 reactors built over 22 years by a population of 4 billion is actually roughly HALF as quick and HALF as many reactors per person that the French achieved a generation ago.

Wind mills and PV panels can not match this 76%

But don’t threat Stephen, these nukes will not be built, no instead most the worlds electricity will still be produced by coal and gas come 2035 of that I am certain

“…but believe those would take a lot more fossil fueled activity than the nuclear approach.”

I’m not following you.

Assume we start from zero. First we must build a nuclear plant. Then we must build the infrastructure to distribute the power from the plant. These are extremely fossil fuel intensive activities

While admittedly delivering low density energy, solar cells deliver this low density energy directly to where it is needed with very little additional infrastructure costs. It must also be remembered that the denser an energy source is, the more inherently dangerous it potentially becomes.

in addition, solar cells can now be produced using technologies that require very little energy on a cost per watt basis. Solar cells can now even be printed

it would be nice if molten salt reactors existed on a commercial scale right now so that we could compare technologies, but they don’t. It will take many years, perhaps decades, and billions in tax payer funded research before commercial scale molten salt plants produce their 1st gW of energy.

In the meantime, solar and solar storge technologies will be advancing very quickly, growing more powerful even as they also grow cheaper and easier to install.

Nuclear plant would directly replace a Coal Plant on the same lot, or next door. No Fictional ” infrastructure to distribute the power from the plant” needed.

Nuclear power generation and coal power generation are compatible, both are thermal power plants, using the Steam Turbines, and the same type of wiring, so also is Concentrated Solar Power too, not so PV or Wind.

Pv and Wind are the ones which require “infrastructure to distribute the power from the plant”

“Nuclear plant would directly replace a Coal Planrt on the same lot, or next door.”

In areas where a sufficient grid already exists, this is true. But most of the world’s additional energy demand in the next 35 years will come from areas with nonexistent or inadequate energy infrastructures.

Nuclear makes much more sense in the developed world, where sufficient grid infrastructures are already in place. But they still face an uphill political and economic battles.

in addition, I find no reason why molten salt technology could not be used to store the excess wind and solar energy from off the grid to help solve internmitency – though I would agree that this would be less efficient than direct production of energy.

I agree that the best way to utilize both solar power and Wind Power is through Molten Salt Storage.

Yet, as I have said before, many Third World Countries Already have Grids, and in addittion, they already have Coal.

We need to replace existing coal fired plants in China, India, Germany, Uk, US., As well as in Africa Too. A nuclear plant will directly displace these Unacceptable Coal fired plants without any modification to the Grid.

The argument of using Molten Salt to store Wind power, while being an excellent suggestion, will require using of Steam Turbine Generators and an Extensive grid to reclaim and distribute the thermally stored power. In addition, feeding in power from all those Thousands of Wind Mills to the Molten Salt reserve require build an addittional, separate Wind Mill Grid.

Your statement that, “But most of the world’s additional energy demand in the next 35 years will come from areas with nonexistent or inadequate energy infrastructures.” as a reason to not use Nuclear power, is incompatible with Molten Salt Storage that youo advocate.

Power stored in Molten Salt will still require a grid to distributethat power to the end user. You can’t have it both ways.

None of the four points in this article are addressed in any detail. So though it is a great article it is just the start. We need more articles addressing these points. I have a lot of opinions on each point. They are probably just opinions and need a lot of factual grounding. Can we see more articles addressing each of the points. I think we all want a more distributed energy system that can be tied together neatly. It would be wonderful if we could ge more information here.

Note that it is possible for the inverters which are used with solar PV systems to provide power-factor correction (this is currently done on some wind turbines), but this feature is only meaningful if the utility has control over the inverter. Utility-controlled inverters can also be programmed to provide frequency regulation, but only if storage is provided.

I recently heard an excerpt of an interview with former US energy secretary Steven Chu. In it, he was saying that the current net-metering model for how owners of PV systems pay for electricity will not work as these systems become more common.

Chu says he’s been talking to utilities about a model wherein utilities own and control the PV systems and batteries that are placed on the customers’ roofs/garages, and customers are given some credit for the use of space. The problem with this model is that unlike net-metering, it does nothing to hide the fact that residential PV costs double what utility scale PV does, and is less compelling as eco-bling.

It’s not very hard to integrate (variable) wind/solar power into power grids when adequate natural gas peaking/intermediate backup power is available and on-line to balance supply-demand. With the exceptions of relatively limited available hydropower pumped storage and very limited geothermal or solar-thermal intermediate power that may be positioned to backup non-dispatchable wind and solar, idled/trimmed-rate natural gas power must be available when the wind stops blowing (or blows to hard) and the sun does not shine.

Besides the power system transmission and distribution losses you have described in this post another factor rarely covered is the hidden costs of increased penetration levels of variable wind/solar and impacts on the efficiency losses (increased fuel consumption per KWh) of idled/trimmed backup natural gas power plants. As you may be aware, all gas/steam turbine generators have variable efficiencies depending on design. Efficiencies are normally maximum in the 70%-100% of design range rates (or turbine-generator speeds as you have referenced), and significantly lower (greater fuel consumption per KWh) when generation capacities are reduced (<60% design) or run at maximum (>100% optimal design). This is a factor that many Utilities are concerned with.

In many cases renewable wind/solar are given priority when grid supply exceeds demand. Rather than trimming the renewable power as needed to stabilize power grids, the backup natural gas power is trimmed, which increases costs. This operational inefficiency will continue until industrial scale power storage is developed and available to store variable wind/solar when supply exceeds demand and allow more optimal operation (reduced fuel per KWh) of natural gas power plant supplies.

I am taking you to task for inferring that grids (infrastructure) have first to be built before Nuclear power can be accomodated.

Here is my direct quote:

Your statement that, “But most of the world’s additional energy demand in the next 35 years will come from areas with nonexistent or inadequate energy infrastructures.” as a reason to not use Nuclear power, is incompatible with Molten Salt Storage that youo advocate. “

Here is a map of African power grids (non ehaustive):

There is NO Difference to the grid between Coal (commonly used and Oil, and Natural Gas), and Nuclear power, if the same Output is being distributed. Hence many countries are capable of using Nuclear Power.

You seem fixated on the notion that there is nothing but Jungle in Africa and either that the grids are non-existent outside of S.Africa (in other words, the Black Nations), or that the grids are unable to use Nuclear Power.

Corruption is the main problem, where systems are not updated sufficiently.

– 60.0% of Ghana’s population has access to the grid (2009), meaning 39.5% do not (mostly in remote locations), so yes major grid modifications and build outs would be required for nuclear to be introduced.

– 48.7% of Cameroon’s population had access to the grid (2009), meaning 51.3% do not (mostly in remote locations), so yes major grid modifications and build outs would be required for nuclear to be introduced.

I think that all three should be mass produced in the most efficient way possible, according to the most watts, 24/7, for the least amount, that is wind, solar and their storage. And they will continue to grow, infact I believe it’s about 40 years until they “power everything” at a 22% yearly growth rate (and assuming storage is built along side after max grid integration of about 20% in about 20 years).

The best nuclear plants need to be developed, but need not take more than a few years because the tech has already been proven for various different concepts. Now, we just have to “optimize”, that is, figure out how to make money of off the fuel delivery (sorry, but it’s a no go unless someone gets rich, just like they do with the LWR, at least it seems that way).

Since “every body” has their own opinion (and has been polarized by their favorite sources), we have a small chance of saving the biosphere. So many conflicing views… and most do not know exactly WHAT IS the best energy source to pursue at this time, much less, even care!

There is actually a very small percent OF US who argue between carbon free sources. What we need to do is get “EVERYBODY” interested in the energy debate. Sure, there would be more confusion, but at least “everybody” would be trying to stop excess CO2. Eventually, a consensus based upon proven facts about “all sources” (The math on energy, political views, media lies, science of excess CO2, etc) would provide the ultimate fast tracking potential, perhaps in the form of a computer program, or game.

“There is actually a very small percent OF US who argue between carbon free sources. What we need to do is get “EVERYBODY” interested in the energy debate. Sure, there would be more confusion, but at least “everybody” would be trying to stop excess CO2.”

Absolutely agree. Energy is the single most important topic to humanity. Cheers.

I did some math. I wish I would have remembered to write it down… And this is NOT the right way to estimate a solar system, however, I’ll give it a try!

Cheapest ebay batteries are under $2/Ah for 12v or about $150 per kWh of storage. I used about 500 kWh (mostly for an electric water heater) in a month. Would like at least 3 days storage, so about 50 kWh 50,000Wh / 12v = 4,166Ah (I’d conserve much more and go with 3,000Ah).

The lead acid must not be fully depleted, I think it’s like 4 years at just 50% discharge but only one year at 90% discharge, so I’d buy $6,000 just to be safe (assuming that in bulk, the better quality ones would be this cheap). Figure 5X that for life of panels?

I want to be able to charge up at least 50% more than I use in the 5 hours of sunlight I have in the winter. Thus, 25,000 watts / 5 = 5,000 watts at about $1 a watt (cheapest availabl) plus wiring, inverter charge controller, (watch out for labor!).

Figure 10 grand for panels, so about $40,000 per family, but wait, what about all the tree shadows, and all the people who don’t have a good sunny location… Ok, let’s say $70,000. (And there’s a bunch of people who do not have their own roof). $70,000 x 110 million house holds (in the U.S.) = 7.7 trillion. That’s IF the enviromentalists would let us dig up all that extra lead and what not!

Wireing for 12 or 24v has to be a lot thicker than for grid voltages (ohms law), thus even though decentralized, solar PV and batteries STILL might take as much materials as a full on grid!

A “grid” costs about… Well, can’t find it but a smart grid might cost almost half a trillion for the U.S…

So also does South Africa. A situation I am very intimately familiar with, and similarly with respect to Nigeria,

Amazingly, you want to tell the Nigerians they are not qualified to have nucllear power. You want to offer a country of 130 Million+ people some PV panels to connect to and light up some LEDs. As I challenged you before, power your own house/cities with these Toys first and then extend them to other, after they’ve been proven to work well.

This not because the grids cannot support Nuclear power, but because they simply need repair to bring the power they do generate to more Nigerians. These grids already run on Oil and Coal, and they will run just fine on Nuclear power as well.

lt won’t be batteries, or if it is, it will be batteries that look and act very much different from current batteries. And they will be much cheaper too. There is a new age coming; an age where materials will be designed at the molecular level to perform specific chemical tasks.

This age is coming much much faster than most realize

The future of energy storage ultimately lies in catalysis – catalysis of water, catalysis of CO2, it lies in the repurposing hydrogen for work in electron transfer chains that men will build from the molecule up extrapolating them from designs found in nature.

Germany installed almost exactly 7.5GW in 2010 in 2011 and in 2012 so no growth at all let alone 22% compounded. Whats more this year is expected to be less so it seems install rate is going to go down.

And this is with PV subsidised from 11 to 16 euro cents per KWh on top of wholesale prices whereas the value of a variable non dispatchable source is closer to just 2-3 cents / kwh.

Can you name a single town or city that has a population above 10.000 and lives a western lifestyle who have decided to cut off from the national grid because their PV and wind are supplying 100% dispatch able reliable power.

At first you used the word “require”. Now you bring in exceptions, “population above 10.000 and lives a western lifestyle.”

As I’ve said several times, solar will start with the poorest of the poor and as it gets better work its way back to the more affluent as each version gets better. There are 1.2 billion without grid access – that’s 20% of the potential world energy market.

“most the worlds electricity will still be produced by coal and gas come 2035…”

I agree. The 50% nuclear threshold is probaby still 40 years away. This is a result of

The longevity of existing fossil fuel power plants. No technology will be able to economically replace these plants before the end of their serice lives.

The failure of developed nations to lead in embracing nuclear. The strength of the anti-nuclear factions within western environmental orgs greatly weakens these groups’ anti-fossil fuel message.

So a lot depends on China. They have skyrocketing new demand, and a fossil fuel industry that seems designed to show fossil fuels in the worst possible light (e.g. the world’s worst worker safety, world’s worst air pollution). If their nuclear industry can at least match Russia’s for quality and safety, China may well follow France to 80% nuclear power; and this would become a model for the developed world.

“Energy storage and generation are complementary, not competitive, technologies.”

This is only true of non-fossil energy systems. All stored energy competes with gas-fired generation, in part because of its low capital cost and rapid throttling.

But the biggest is the central role of gas fired generation in meeting summer peak generation capacity. Failure to understand this central issue has handicapped the renewable energy roll outs. Wind and cloudy-town PV do not eliminate the need for any natural gas capacity. This means the combined cost of renewable generation and storage must compete with the fuel-cost of gas (not the complete levelized cost). Geothermal and desert CSP with storage (below 15% penetration) would not have this problem.

You’re right that inverters can be designed to provide power factor control, but their lack of inertia relative to rotating equipment makes it harder for them to provide voltage support and spinning reserve.

Quite right and a good point – many subtleties that were omitted from the post in the name of simplicity, but particularly for spinning reserve, rising wind penetration is increasing the need for gas turbines to run in hot standby with the breakers open so that they can quickly ramp up (e.g., 0% fuel efficiency) or to run at part load so they can quickly ramp down. Not universally true for wind of course, but also clearly not ideal from an environmental or cost perspective.

Yes, it is easy to imagine that solar could drop in cost by another 50% or so. That would allow it to beat out wind in many locations.

However, if batteries dropped in cost by another 50-80%, that would make electric cars more successful, but would not change the prohbitively bad economics of cloudy-day grid storage!

The big win for desert solar power is 5 hours of storage. That makes it a peaking power source which can compete with natural gas. In non-desert locations, in which clouds can block solar product for 1, 2, or even more days in a row, batteries (and solar salt) are simply not a credible solution.

A grid connected power system with thermal generation for backup will always be the predominant solution. Off-grid power in energy-rich nations is a fantasy.

Note that for the off-grid question, there is a big difference between densely populated areas (cities and suburbs) and rural areas. In the early 1900s, the US struggled with the economics of rurual electrification using a grid; so rural areas in developing nations may in fact be better served with off-grid solutions such as solar and wind with reversible fuel cells for energy storage (or batteries with sufficient breakthroughs).

But with modern farming practices, only 2% of the population can feed everyone else, so these rural solutions will always be small compared to the grid solutions used in cities.

Cities, because of their density, are good for the environment, because they minimize the energy cost of personal transportation. They also provide the workforces that make all of the other products society needs. But they are too dense to supply themselves with renewable energy, hence the need for grids to bring energy from elswhere.

Remember what they say about predicting scientific advances: we’re always too optimistic in the short term, and too pesimistic in the long term.

We like to think that science will soon bring the solutions we want (ie. cure to the common cold, easy weight loss, cheap energy storage). In fact, science ususally brings us solutions to problems that we didn’t even know we had! (e.g. transistors, the internet, texting, microwave ovens, fracking, etc).

Yes, I agree: solar power with fuel sythesis for energy storage is a technically viable solution to reliable and sustainable electricity production (although I would argue that ammonia synthesis is simpler and much more efficient than methanol, which would fully offset the greater toxicity. Remember that methanol fuel cells are limited to 35% efficiency, whereas ammonia fuel cells can approach the same efficiency as H2. also note that either way, the fuel is “carbon neutral” not “carbon negative” since the carbon is re-released upon combustion; this is different than biofuels which leave carbon in the soil).

However, as of today, solar with fuel synthesis for electric storage would be something like triple the cost (on average) of nuclear power, and the night-time and cloudy-day power would be even more (assuming a generous 40% round-trip efficiency), and double again in cloudy locations like Japan or Northern Europe. Better to use the synthetic fuel for high-value applications like transportation.

So it seems to me that the solar path (in non-desert locations) inevitably leads to continued fossil fuel use on cloudy days (particularly abundant, low value fuels like coal).

Here is a 2005 UC Berkeley paper comparing the material inputs (particularly steel and concrete) to different nuclear reactor technologies. Figure 1 also shows a datapoint for wind, which uses one order of magnitude more steel per unit electrical output than nuclear, and coal which uses double that of nuclear, and natural gas which is much lower than all others.

Off-shore wind will be even worse, since in most locations they have underwater foundations that are more massive than the towers themselves, and the “superior offshore winds” really only boost capacity factor by 10% or so (to 45% vs. 35%).

The article itself touts the benefits of the AHTR (a molten-salt cooled reactor, with TRISO fuel). LFTR and DMSR would have similar plant material inputs, but of course would be indefinitely scalable and sustainable.

Nathan, in this particular field of study, the term “as of today” almost does not apply any longer and “as of this hour” is becoming more fitting.. Do yourself a favor; enter the term “solar fuels cataliysis” into google and set the time limit for only the last week. You will see pages upon pages of relevant information.

I can almost guarantee that by the time even Vogtle is built, that research in this rapidly advancing technology will come up with things that will blow your mind.

I envision enormous solar catalytic mats laid out on the sun-baked waters of our planets ocean deserts. These areas are huge, the sun is always strong, the waters are almost always calm and the geography is free

I used to envision, but in today’s world, that costs too much. So I would envision machines that could make it all very much cheaper in the future, but that still costs too much, in the form of CO2 being emitted in today’s world, that is, because of all the confusion (because everybody else wants machines to make their fave cheaper, too). Thus there is no real consensus.

Best just to go for the cheapest, most abundant source already available and make (or erase) laws necessary to that end.

I bet, out of 100 physicists, 97 would say “The quickest to stop excess CO2 is to deploy the safest nuclear reactor on a global scale).

Solar and solar catalysis is and will continue to become cheaper with each rapid iteration. Molecular Chemistry will beat out nuclear physics – possibly even before Vogtle is completed

Please don’t forget that methanol production from solar catalysis could be carbon NEGATIVE and has the very possible capacity to actually reverse the upward CO2 trend in our atmosphere. Nuclear can not do this.

I hope you are right, concerning solar catylist, that its efficiency will become at least on the order of PV. Concerning methanol, it can not be carbon negative unlest CO2 is sequestered. geological sequestration is worst than storing nuclear wastes underground because CO2 does not “decay”. Mineral sequestration is like turning CO2 into a rock… perfect (but we need LOTS of energy to do this, on the order of being 70% efficient).

But methanol would be cool, just that it takes a LOT of energy to make, also (unless steam reformed from NG, but then, why bother).

A recent article from Solar Novus Today discussed that the nature of the global solar market is becoming more distributed. While the total size of the market will remain steady between 100 GW and 120 GW across the year, the number of markets with..

Distributed generation has been a niche player in the electric power industry. This could change rapidly as the cost of storage declines. The biggest obstacle to rapid growth in distributed power is the complexity of analyzing the value of storage.

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